The present invention relates to a method of poling a ferroelectric crystalline body. It also relates to a method of clarifying the transparency of a ferroelectric crystalline body.
Significant uses are being found for ferroelectric crystalline bodies having regions of differing ferroelectric domains. For example, bodies having sequential and adjacent regions differing of are being used to obtain second harmonic generation (SHG) of optical radiation via quasi-phase-matching. The present invention enables the production of such a body which implements quasi-phase-matching as described in Bloembergen U.S. Pat. No. 3,384,433 in a superior way. (As used herein, the terminology "optical radiation" means electromagnetic radiation in the visible wavelength spectrum and in other adjacent wavelength spectrums--typically radiation having a wavelength in the range of between 100 and 100,000 nanometers). Radiation having a wavelength of about 0.43 micrometers (blue light) is achieved from 0.86 radiation obtained typically from a GaAlAs diode laser, by quasi-phase-matched second harmonic generation in a periodically polled crystalline body. This wavelength of radiation is particularly valuable for optical storage and other uses.
Patent application Ser. No. 07/305,215 filed Feb. 1, 1989 for NONLINEAR OPTICAL RADIATION GENERATOR AND METHOD OF CONTROLLING REGIONS OF FERROELECTRIC POLARIZATION DOMAINS IN SOLID STATE BODIES, naming two of the inventors hereof, describes methods applicable to achieving reversed polarization in existing ferroelectric crystalline bodies having dominant polarities. One approach described in such application is the patterned introduction of selected dopant materials into a solid state, ferroelectric crystalline body. Another approach that is described is to apply electric fields to an existing solid state body having a dominant polarity. The procedure of creating regions of different dominant polarities is referred to in the art as "poling".